Improvement in calipees



' G. L. MCKNIGHT.

Calipers. No. 65253. Patented May 28. 1867.

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@geiten tetris stwt @fitta L. MCKNIGHT, CF WORCESTER, MASSACHUSETTS Letters Patent No. 65,253, dated Vey 28, 1867. Y

IMPROVEMENT IN GALPERS.

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KNOWV ALL MEN BY THESE PRESENTS:

That I, Gr. L. MGKNIGHT, of the city and county of Worcester, and Commonwealth of Massachusetts, have invented certain new and useful Improvements in Calipers, Dividers, and Draughting Instrument-s; and I do hereby declare that the following is a full, clear, and exact description oi' the same, reference being had to the accompanying drawings forming a part of this specification, in whichv Figure 1 represents a. side View of so much of a ealiperior other similar instrumen as is necessary to illustrate my invention.

Figure 2 represents a vertical central section on line A B, g. l.

Figure 3 represents a cross-section on line C D, same figure; and

Figure 4 represents a side view of one arm of a caliper.

In the drawings the part marked A represents the body of the instrument, in which are slots a a to receive the upper ends of the forks, arms, or legs of the instrument, which are pivoted to the body at the points b b., From the upper part of Arises the standard B, upon which is cut a thread, e, to it the screw-thread d in the nut C. The upper end of the standard ci is bored out, aud is a so provided with slits e e; one or more may be used. A. screw, D, is fitted to work into the top of the standard B, as clearly indicated in the drawings. E is a spring which passes through a hole in the top of the part A, and as the hole is a little smaller indiameter than the width of the spring E, the latter when driven in is retained in a very secure position. The endsff of the spring are bent down into the slots a a before the arms or forks of the calipers or other instruments are hinged or pivoted to the part A, southat the endsff, of spring E, acting upon the arms or forks of the instrument, cause them to expanduntil their upper ends, which are to be made in the form shown in iig. 4, strike against the nut C, which can be screwed up or down upon the standard B, to adjust the lower ends of the arms of the calipers or other instrument to the desired distance apart, when, by turning screw D down, the slotted end of standard B is expanded, thereby binding nut C securely in the desired' position to hold the arms, forks, or legs of the instrument in the proper `position for use.

It will be seen that 'after the instrument is once adjusted for use, which can be readily done, there is no danger of displacement of the parts either by handling, dropping, or otherwise.

My invention is designed. to ohviate the use ofthe expensive springtop caliper, divider, and similar instruments. As applied to calipers it answers equally well for those used for calipering inside as Well as outside surfaces. In lieu of a flat spring,'E, a small spiral spring may be pla-ced in the hole g, to force `the arms or forks apart.

Having described my improvements incalipers and other similar instruments, what I claim as new, and of my invention, and desire to secure by Letters Patent, is-

1. The combination, with the slotted standard or screw B, ofthe screw D, for holding the adjusting-nut C, substantially as described. Y l

2. The combination, with the upper part of the body or part A, of the spring E, substantially as and for the purposes set forth. v

G. L. McKNIGHT.

Witnesses: l

'lnos.` 1I. Denen, l). L. Mumien. 

